Method of producing diamond grinding and lapping implements



Patented Sept. 26, 1939 UNI-TED STATES METHOD OF PRODUCING DIAMOND GRIND- ING AND LAPPING IMPLEMENTS Gottlieb Barth-Vuilleumier, Nidau-Biel, Switzerland No Drawing. Application October 15, 1937, Serial No. 169,295. In Switzerland October 24, 1936 1 Claim. I (Cl. 51-278) This invention relates to methods of producing diamond grinding and lapping implements. Hard minerals, such as sapphire, ruby, garnet, agate and the like are preferably worked by 5 means of diamond bort due to the fact that the latter is of much greater hardness than the first-named minerals. Furthermore, there are quite a number of hard metal alloys which owing to their great hardness can be worked by means of the ordinary carborundum grinding wheels only with difliculty and by using a great amount of time and with considerable expense. Therefore, the need exists for new lapping implements which are capable of performing not only fine but also rough and quick grinding work without smearing and which, apart from this, require no complicated special expedients.

It has heretofore been proposed to mix diamond powder with corundum powder and an artificial resin with fibrous material and heat same in molded shape and with pressure to condense the resin. -Implements so formed have thedisadvantage that in use the resin becomes soft so that the implements become smeary and rapidly disintegrate.

It has also been attempted to mix diamond dust with terra cotta and, after molding the implements, to burn the same at high temperature, but the results were-unsatisfactory as the diamond was impaired as to its abrasive quality and the action of 'the diamond, when grinding wheels were concerned, was too rough and ripping.

According to the present invention a method is provided by means of which grinding wheels and other lapping implements can be produced from diamond particles by mixing the same with pulverised sapphire (corundum), carborundum, boron carbides or particles of other lapping materials and binding them by a ceraniicprocess without risk of the diamond bort being damaged by the great heat required therefor. With the use of grinding wheels of this kind the hardest minerals, hard metals or other hard materials can be roughed in a surprisingly short time or be finely or sharply ground depending upon the choice of size of grain, whilst the wear on the implement is very small compared to its high efllciency.

Advantageously, diamond particles, that is, di-

upon the widely varying purposes for which, as 10 is Well known, lapping implements areused in practice, the composition of the mixture is varied. By way of example, 7 parts of pure diamond-powder, 2 parts of synthetic sapphire, 1 part of calcined alum, 2 to 5 parts of ceramic l5 binding material containing silicic acid (depend,- ing upon the hardness required), 3 parts of glycerine, 4 parts of glue-size are mixed, molded and burnt at high temperature. The burning temperatme may vary considerably, depending 20 7 upon whether very hard or relatively soft lapping implements are to be produced. Moreover, the composition recited above must naturally be adapted to the purpose which the implements are to serve.

As the binding material ceramic substances containing silicic acid, such as quartz, silicates for instance feldspar, Water-glass or glass-powder may be used singly or in combination with alum earth. The thus burnt lapping materials 30 may be applied to the practical working methods in the state as produced or after having been mounted on metal cores or attached to metal supports of various shapes, in dependence upon requirements.

Various changes and modifications may be made inmy invention without departing from its principle by simply applying customary practice and established knowledge of the art to' the present' disclosure. 40

What I claim is:

In a method of producing diamond lapping implements, the steps of mixing diamond particles with particles of a hard mineral and with a ceramic binding material containing silicic acid, 45 molding said mixture, and uniting said particles by burning said mixture.

GOTTLIEB BAR'I'H-VUIILEUMIER. 

